ADDED: stri_wrap in c++ and new version of stri_wrap in R (stri_wrapC3). sapply has been replaced with stri_wrap in c++ which is about 2-3 times faster. New version uses stri_split_fixed to split string by " " and this need to be changed when stri_split_regexp will be done.
UPDATE: stri_split_pos - 'from' is the first char to copy and 'to' is the last char to copy.
ADDED: new tests and benchmarks for stri_wrapC3